Thread: ps_status on fastpath
I noticed that the fastpath code doesn't update ps_status, which would be harmless except that it leads to "idle in transaction" being logged in log_line_prefix for the command tag. Are there objections to applying this? -- Álvaro Herrera <alvherre@alvh.no-ip.org>
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Alvaro Herrera <alvherre@alvh.no-ip.org> writes:
> I noticed that the fastpath code doesn't update ps_status, which would
> be harmless except that it leads to "idle in transaction" being logged
> in log_line_prefix for the command tag.
> Are there objections to applying this?
Hm, what about pgstat_report_activity()?
Is anyone concerned about the added overhead for fastpath calls?
regards, tom lane
Excerpts from Tom Lane's message of vie dic 17 12:41:06 -0300 2010: > Alvaro Herrera <alvherre@alvh.no-ip.org> writes: > > I noticed that the fastpath code doesn't update ps_status, which would > > be harmless except that it leads to "idle in transaction" being logged > > in log_line_prefix for the command tag. > > > Are there objections to applying this? > > Hm, what about pgstat_report_activity()? I wasn't sure about that, because of the overhead, but now that I look at it, it's supposed to be cheaper than changing the ps_status in some cases, so I guess there's no harm. The other argument to support the case that this should be done is that the docs suggest that you should use prepared statements instead, which do have the reporting overhead. -- Álvaro Herrera <alvherre@commandprompt.com> The PostgreSQL Company - Command Prompt, Inc. PostgreSQL Replication, Consulting, Custom Development, 24x7 support
Alvaro Herrera <alvherre@commandprompt.com> writes:
> Excerpts from Tom Lane's message of vie dic 17 12:41:06 -0300 2010:
>> Hm, what about pgstat_report_activity()?
> I wasn't sure about that, because of the overhead, but now that I look
> at it, it's supposed to be cheaper than changing the ps_status in some
> cases, so I guess there's no harm.
Yeah, if we can afford a possible kernel call to set ps status, it
doesn't seem like pgstat_report_activity should be a problem. I'm
also of the opinion that more people look at pg_stat_activity than
ps output these days.
regards, tom lane
Excerpts from Tom Lane's message of vie dic 17 16:25:17 -0300 2010: > Alvaro Herrera <alvherre@commandprompt.com> writes: > > Excerpts from Tom Lane's message of vie dic 17 12:41:06 -0300 2010: > >> Hm, what about pgstat_report_activity()? > > > I wasn't sure about that, because of the overhead, but now that I look > > at it, it's supposed to be cheaper than changing the ps_status in some > > cases, so I guess there's no harm. > > Yeah, if we can afford a possible kernel call to set ps status, it > doesn't seem like pgstat_report_activity should be a problem. I'm > also of the opinion that more people look at pg_stat_activity than > ps output these days. Well, actually, if the functions are cheap, presumably they aren't going to stay for much time in either status report; what I'm after is fixing the log_line_prefix stuff (%i I think it is). -- Álvaro Herrera <alvherre@commandprompt.com> The PostgreSQL Company - Command Prompt, Inc. PostgreSQL Replication, Consulting, Custom Development, 24x7 support
Excerpts from Tom Lane's message of vie dic 17 12:41:06 -0300 2010: > Alvaro Herrera <alvherre@alvh.no-ip.org> writes: > > I noticed that the fastpath code doesn't update ps_status, which would > > be harmless except that it leads to "idle in transaction" being logged > > in log_line_prefix for the command tag. > > > Are there objections to applying this? > > Hm, what about pgstat_report_activity()? Just noticed that it's already handled in postgres.c, before calling HandleFunctionRequest. Probably not worth messing with. -- Álvaro Herrera <alvherre@commandprompt.com> The PostgreSQL Company - Command Prompt, Inc. PostgreSQL Replication, Consulting, Custom Development, 24x7 support
Alvaro Herrera <alvherre@commandprompt.com> writes:
> Excerpts from Tom Lane's message of vie dic 17 12:41:06 -0300 2010:
>> Hm, what about pgstat_report_activity()?
> Just noticed that it's already handled in postgres.c, before calling
> HandleFunctionRequest. Probably not worth messing with.
Ah. Well, the ps_status update should be adjacent to the other one,
not off in some other module altogether.
regards, tom lane
Excerpts from Tom Lane's message of vie dic 17 18:21:48 -0300 2010: > Alvaro Herrera <alvherre@commandprompt.com> writes: > > Excerpts from Tom Lane's message of vie dic 17 12:41:06 -0300 2010: > >> Hm, what about pgstat_report_activity()? > > > Just noticed that it's already handled in postgres.c, before calling > > HandleFunctionRequest. Probably not worth messing with. > > Ah. Well, the ps_status update should be adjacent to the other one, > not off in some other module altogether. Agreed -- committed that way. -- Álvaro Herrera <alvherre@commandprompt.com> The PostgreSQL Company - Command Prompt, Inc. PostgreSQL Replication, Consulting, Custom Development, 24x7 support